Hi there I was wondering 2 things. In order for a plasma chain to work on an asset do you need a corrosponding ERC20/ERC721 token on the ethereum mainchain first? I am thinking of using BTCRelay type of thing to essentially lock coins on a bitcoin based altcoin and creating an asset on ethereum with the hopes that I can go directly to plasma without issues a mainnet transaction, is this possible?

The second thing is, if I create a parent plasma chain and create a bunch of children plasma chains under me, can I make it so that the children plasma chains have to pay some fee from the parent plasma chain?